Corrosion inhibited antifreeze compositions



United States Patent poration of Delaware N0 Drawing. Filed Mar. 26,1963, Ser. No. 267,923 6 Claims. (Cl. 252-75) This application is acontinuation-in-part of copending parent application Serial No. 120,158,filed June 28, 1961.

This invention pertains to novel corrosion inhibited antifreezeformulations and to aqueous solutions thereof. It particularly relatesto an antifreeze which can be stored in metal containers, especiallyiron containers, for long periods of time at elevated temperatureswithout precipitates forming therein and without the container beingattacked by the antifreeze to the extent the antifreeze leaks therefrom.The invention also concerns a method of producing the antifreezeformulations and their aqueous solutions. In addition the inventioncovers a method for-preventing corrosion of metals which come in contactwith the antifreeze formulation.

The parent application describes antifreeze compositions of outstandingcorrosion inhibiting effectiveness in aqueous heat exchange systems,such as the cooling system of an automobile. However, these describedant freeze compositions, as do many of the commercial antifreezes, inundiluted form are corrosive to their metal containers, such as steelcans and black iron drums, under storage conditions. The results of thisattack after a period of time are leaks developing in the antifreezecontainer and precipitates forming in the antifreeze. Leaks are ofcourse undesirable since antifreeze is lost and the salability of thepackaged antifreeze becomes markedly reduced. Further, the precipitatesformed in the antifreeze build up consumer sales resistance even thoughthe precipitates may not affect the corros1on 1nhibiting properties ofthe antifreeze.

The storage deterioration is thought caused by the fact that whenundiluted antifreeze is stored for long periods of time particularlyunder the elevated temperature conditions encountered in outdoorstorage, the combination of freezing point depressant and inhibitorsattacks the iron container. Specifically, it is believed the ironcontainer is attacked by the antifreeze components to form ferric oxide.It is further believed the formed ferric oxide functions as a catalystto accelerate the corrosion of the container. The results is pinholeleaks in the container and precipitates resulting from the reaction ofiron with the various antifreeze components. By the term iron we alsointend to include steel.

It is interesting to note that an antifreeze whlch may be satisfactorilycorrosion inhibited under heat exchange conditions, such as in anautomobile coollng system, may be unsatisfactorily inhibited for longterm storage conditions since the conditions are essentially different.Further, under storage conditions even a minor amount of corrosion wouldcause puncturing of relatively thin container walls over a long periodof time.

In the past, one method of preventing corrosive attack of undilutedantifreezes on their iron storage containers was to tin plate or coatsaid containers with an inert plastic material (polyethylene). Althoughthe tin plated surface is resistant to antifreeze attack, the tincoatings were often damaged at the containers seams during the crimpingand metal joining procesess, leaving portions of the underlying ironbody exposed to attack. The coating of the inner surfaces of the steelcontainers with an organic plastic substance is highly effective inpreventing corrosion. However, the plastic lining of containers isrelatively expensive. In the highly competitive field of antifreeze anyadded cost is significant.

Accordingly, it is an object of this invention to provide an antifreezeformulation in concentrated (undiluted) form which can be stored inrelatively inexpensive, unlined iron containers and tin platedcontainers for extended periods of time without leaking from saidcontainers and without forming undesirable precipitation therein.

Another object of this invention is to produce an antifreeze formulationwhen in an aqueous system affords sunperior corrosion protection tometals normally found in heat exchange apparatus.

Still another object is to provide a method of forming the antifreezecompositions of the invention.

Further objects of the invention will become apparent from the remainingdisclosure.

In accordance with this invention and the objects thereof, we havediscovered that the incorporation of a combination of an alkanolamineand alkylenediamine tetra alkanoic acid or alkali metal salts thereof inthe antifreeze compositions as described in Serial No. 120,- 158 resultsin a synergistic increase in the period of time that said compositionscan be stored in iron or tinplated containers without undesirableprecipitates forming therein and without the antifreeze leakingtherefrom. The antifreeze compositions as disclosed in the parentapplication comprise a water soluble liquid alcohol freezing pointdepressant and a corrosion inhibiting agent comprising alkali metaltetraborate, alkaline earth metal tetraborate, alkali metal metaborate,alkaline earth metaborate, alkali metal mercaptobenzothiazole and analkali metal arsenite. It is also taught therein that a separate oilphase may be optionally included with the antifreeze compositioncomprising a lubricating oil solution of a carbon dioxide neutralizedbasic alkaline earth metal sulfonate of a molecular weight between 900and 1500. The addition of the sulfonate lube oil phase has been found tofurther increase the overall inhibiting action.

The freezing point depressants which may be utilized are any of thewater soluble, water immiscible liquid alcohols, such as monohydroxylower alkanols, and the liquid polyhydroxy alcohols such as the alkyleneand dialkylene glycols. Specific examples of the alcohols contemplatedare methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol,diethylene glycol, propylene glycols, butylene glycols and mixturesthereof. A preferred alcohol is ethylene glycol and when soldcommercially often contains a small amount, up to about 10% by weight,of diethylene glycol. The term ethylene glycol as used is to read eitheron the pure or commercial form. This is also true for the other freezingpoint depressant alcohols contemplated. The freezing point depressantadvantageously comprises between about and 99 wt. percent, preferablybetween and 96 wt. percent, of the nonaqueous antifreeze, the remainderof the nonaqueous antifreeze being substantially the corrosioninhibiting agent and storage stability additive.

The corrosion inhibiting agent advantageously is present in theantifreeze compositions of the invention in an amount between about 1and 9 wt. percent preferably between 2 and 4.5 Wt. percent, based on theweight of the water-soluble alcohol and preferably comprises betweenabout 24 and 27 wt. percent alkali metal tetraborate, between about 36and 45 wt. percent alkali metal metaborate, between about 4 and 5 wt.percent alkaline earth metal tetraborate, between about 6 and 10 wt.percent alkaline earth metal metaborate, between about 3 and 4 wt.percent alkali metal mercaptobenzothiazole and between about 13 and 22wt. percent alkali metal arsenite. A preferred specific inhibitorcombination is sodium tetraborate decahydrate (borax), sodiummetaborate, calcium tetraborate, calcium metaborate, sodiummercaptobenzothiazole and sodium arsenite. Other examples ofcontemplated metaborates, tetraborates, arsenites andmercaptobenzothiazoles are potassium metaborate, potassium tetraborate,magnesium metaborate, magnesium tetraborate, barium tetraborate,potassium mercaptobenzothiazole, and potassium arsenite. We includewithin the definition of the metaand tetraborates the hydrous as well asthe anhydrous forms thereof.

As heretofore stated, the parent application also encompasses acorrosion inhibiting oil phase in combination with the inhibitedfreezing point depressant. The added oil phase advantageouslyconstitutes between about 0.5 to 2.5 vol. percent, preferably between0.75 and 1.25 vol. percent, based on the volume of the freezing pointdepressant. The oil phase itself desirably comprises between about 0.5and 5 wt. percent of an oil soluble CO neutralized alkaline earth (e.g.,barium or calcium) metal hydrocarbon sulfonate having a molecular weightof between about 900 and 1500 and between about 95 and 99.5 wt. percentof a lubricating oil.

By the term CO neutralized basic alkaline earth metal hydrocarbonsulfonate it is intended to include approximately an equimole mixture ofalkaline earth metal hydrocarbon sulfonate and alkaline earth metalc-arbonate, said mixture derived from the CO treatment of the productresulting from the reaction of a hydrocarbon sulfonic acid withapproximately twice the stoichiometric amount of alkaline earth metaloxide (e.g., BaO, CaO) or hydroxide (e.g., Ba(OH) or Ca(OH) Examples ofthe sulfonic acids contemplated herein are the petroleum sulfonic acid,such as the mahogany sulfonic and green sulfonic acids. One particularsuitable class of sulfonic acid is the alkaryl and dialkaryl sulfonicacids such as the alkylbenzene and dialkylbenzene sulfonic acids wherethe total number of alkyl carbons is in the 6 to 30 range. A specificexample of a C0 neutralized sulfonate is a C0 neutralized basic bariumalkylbenzene sulfonate having a molecular weight of between about 1100and 1300, and a barium content of between about 21 and 25 wt. percent.

Specific examples of the lubricating oils contemplated in the oil phaseare the paraffinic and naphthenic lubricating oils having a SayboltUniversal viscosity between about 50 and 100 at 100 F. and an APIgravity between about 20 and 28.

A preferred oil phase consists of 2.5 wt. percent CO neutralized basicbarium dialkylbenzene sulfonate having a molecular weight of about 1232and a barium content of about 22.2 wt. percent and 97.5 wt. percent of anaphthenic lubricating oil having a gravity between 22 and 25 API, and aSaybolt Universal viscosity at 100 F. of between 70 and 75.

Water may be combined with the antifreeze compositions in any and allproportions to form the aqueous antifreeze solutions thereof. When theaqueous solutions of the antifreeze composition are to be used incooling systems, the water miscible freezing point depressant shouldgenerally constitute at least about 10 vol. percent, preferably betweenabout 20 and 60 vol. percent of the aqueous antifreeze solution. Thecorresponding water content, therefore, constitutes less than about 90vol. percent, preferably between about 40 and 80 vol. percent of theaqueous antifreeze solution.

As heretofore stated, it has been found, and this constitutes aninvention, that the combination of alkylenediamine tetraalkanoic acid oralkali metal salt thereof and an alkanolamine when incorporated in theabove described antifreeze of the parent application synergisticallyincreases the storage time of the aforedescribed antifreeze compositionin respect to freedom from container leakage and precipitate formationand further substantially reduces the corrosiveness of the antifreeze tometals normally found in heat exchange systems such as brass,

copper, solder, steel, cast iron and aluminum.

The alkanolamines contemplated herein are of the formula:

(HOR) NH where R is an alkylene radical from 2 to 3 carbons and y is awhole integer from 1 to 3, inclusively. Specific examples of thealkanolamines contemplated herein are ethanolamine (EA), diethanolamine(DEA), triethanolamine (TEA), propanolamine (PA), dipropanolamine (DPA),and tripropanolamine (TPA).

In respect to the alkylene diamine tetraalkanoic acid, and salts thereofcontemplated herein, they can be represented by the formula:

where R is an alkylene radical from 2 to 3 carbons, R is an alkyleneradical from 1 to 3 carbons, and Z is a member selected from the groupconsisting of hydrogen, alkali metal and mixtures thereof. Specificexamples of these salts contemplated herein are tetrasodium salt ofethylenediamine tetraacetic acid (tetra Na salt of EDTA), tetrasodiumsalt of propylenediamine tetrapropionic acid, ethylenediaminetetraacetic acid and dipotassium salt of ethylenediamine tetrapropionicacid.

Our storage stability additive combination is advantageously present inthe contemplated inhibited antifreeze formulation in an amount betweenabout 0.05 and 0.8 wt. percent, and in a weight ratio of alkanolamine toalkylenediarnine tetraalkanoic acid material of between about 1:1 and1:2.

It is theorized that the combination of the amine alkanoic acid-salt andalkanolamine functions in the undiluted environment contemplated hereinin reducing precipitates and container leakage by forming a complex withany reactive iron ions whether they be in the antifreeze solution or thewall of the iron container thereby preventing these ions from formingferric oxide, the latter functioning as a catalyst for the furtherantifreeze attack on the iron containers. It is further theorized anyferric oxide that is formed is also comp-lexed by said combinationthereby preventing the formed ferric oxide from acting as a catalyst forantifreeze deterioration of iron containers.

In the preparation of the antifreeze combinations of the subjectinvention, it is desirable to first make up a con centrate of theantifreeze for storage and/or transportation and prior to packagingantifreeze for retail distribution. The antifreeze concentrate can besubsequently diluted with additional freezing point depressants to bringthe ingredient content to the desired level. A particular method isrequired for preparing the antifreeze formulation contemplated herein inorder to prevent undesirable gelling and the formation of insolublealkaline earth arsenites in the final antifreeze composition.

To between about and of the total amount of freezing point depressant tobe used, there is added at a temperature between about 195 and 205 F.with agitation alkali metal tetraborate, boric acid, and an alkalineearth metal oxide. The agitation is continued and temperature maintaineduntil solutioning of substantially all the ingredients occurs. The boricacid and alkaline earth metal oxide react to form a mixture of alkalineearth metal tetraborate and alkaline earth metal metaborate. At thispoint the reaction mixture is preferably filtered to remove anyprecipitate and the temperature reduced to between about and 180 F. Tothe thus cooled reaction mixture alkali metal mercaptobenzothiazoletogether with sodium hydroxide is added either as a solid or aqueoussolution. Additional freezing point depressants may also be introducedat this point. The resultant mixture is stirred until solutioning of theadditional ingredients occurs. The reduction of temperature at thispoint is required to prevent the decomposition of the alkali metalrnercaptobenzothiazole into dibenzyldisulfide. Dibenzyldisulfide is aninsoluble precipitate and thereby eliminates mercaptobenzothiazole as aneffective inhibitor. It is to be noted at this point the alkali metalhydroxide addition converts part of the alkali metal tetra'borate intoalkali metal metaborate.

To the resultant solution the storage stability additive combination ofan alkanolamine and the alkylenediamine tetraalkanoic acid material isadded with agitation. The remaining freezing point depressant is thenadded at ambient temperature (e.g., about 98 F.) together with thealkali metal arsenite immediately after the stability additive additionor at a later period of time. Following this step the sulfonate oil, itto be employed, is added to the finished single-phase antifreezesolution at ambient temperature to form two-phase antifreeze.

Alternatively, the addition of the alkanolarnineamine alkanoic acidstorage stability combination can be delayed to follow the addition ofthe arsenite or sul-fonate oil phase. The resultant singleand two-phaseantifreezes are now ready for storage and/ or addition to water for usein heat exchange systems.

In the foregoing method, if the alkali metal arsenite is added prior tothe addition of the remaining alcoholic freezing point depressant, anundesirable gel is formed together with an alkaline earth arsenite whichis insoluble in the liquid freezing point depressant solution, both ofwhich are difficult to redissolve.

The following examples serve to illustnate the invention but are not tobe interpreted as limitations thereof:

EXAMPLE I This example illustrates the method of preparing theantifreeze combination of the invention.

' To 17,539 pounds of ethylene glycol maintained in agitation at atemperature of 200 F., there is added with stirring 3780 lbs. borax, 567pounds b-oric acid, 227 lbs. lime. The resultant mixture is filtered andthe filtrate is cooled to 150 F. and 760 lbs. of a filtered aqueousethylene glycol solution of sodium mercaptobenzothiazole (water:ethyleneglycol:rnercaptobenzoth-iazole weight ratio of 2: l: 1), 945 lbs. of a50 wt. percent aqueous solution of sodium hydroxide, and 189 lbs. ofwater are mixed into the filtrate. The filtrate is cooled to 140 F. andthere is added 190 Lbs. of triethanolam-ine and 190 lbs. of thetetrasodium salt of ethylenediamine tetraacetic acid with agitation toform a concentrate suitable for bulk shipment.

Subsequently, to 23,628 lbs. of concentrate, 162,994 lbs. of ethyleneglycol and 1890 lbs. 'of a 50 wt. percent aqueous arsenite solution and48 8 lbs. of water simultaneously is added with stirring at ambienttemperature. The resultant undiluted antifreeze is of the followingcomposition: 1'

Composition Percent by weight Ethylene glycol 95.30 Borax 0.80 Sodiummetaborate 1.25 Calcium tetraborate 0.10 Calcium metabonate 0.25 Sodiummercaptobenzothiazole 0.10 Sodium arsenite 0.50 Triethanolarnine 0.10Tetrasodium salt Ethylenediamine 0. 10 Tetraacidic acid Water 1.50

The water in the above composition is not an essential ingredientthereof and it is derived from the use of aqueous solutions, water ofreaction, and from the additional water to facilitate the formation ofthe composition.

EXAMPLE 11 This example illustrates the preparation of a two-phaseantifreeze.

To 189,000 lbs. of single-phase antifreeze prepared by the method ofExample I, there is added 1,537 lbs. of an oil solution consisting of2.5 wt. percent of CO neutralized basic barium dialkylbenzene sulfonateof a molecular weight of 1,232 having a barium content of 22.2 wt.percent and 97.5 wt. percent of a naphthenic lubricating oil of agravity of 23 API and a Saybolt Universal viscosity at F. of 73. Theresultant mixture forms two separate layers. The bottom layer 99 vol.percent of said mixture is the antifreeze of Example I. The remaining 1vol. percent constituting the top layer is the sulfonate oil formulationdescribed immediately above.

EXAMPLE III This example illustrates the corrosion inhibitingeffectiveness of the antifreeze composition of the invention in a heatexchange system.

The corrosion test employed, and which is described directly below,simulates conditions under which corrosion of oxidizable metals isfrequently encountered in a-utomotive engine systems containinganti-freeze coolants.

A clean, open-top, Pyrex glass cell is fitted with two air inlet tubesrespectively connected to the bottom and the middle of the cell, bothjoining outside the cell to form a single inlet tube, and an air outlettube connected to the upper side of the cell. One hundred fiftymilliliters of a 25 wt. percent antifreeze solution in water is chargedto the cell. The water used to dilute the antifreeze h as a 200 ppm. (byweight) chloride ion concentration. The air outlet tube is connected toa water cooled condenser and the joined inlet tubes are connected to acompressed air source. The open top of the cell is closed with a newrolled cork through which is passed a glass rod ending in a hook fromwhich a bundle of test metal strip is suspended by the Nichrome wire.The test bundle comprises clean and weighed test metal strips of copper,brass, solder, cast iron, steel and cast aluminum having a known surfacearea. The test metal coupons are re movably mounted on a brass bolt andspaced with stainless steel washers. The bolt is tightened with a brassnut to hold the test metal strips rigid. This arrangement galvanicallycouples the individual metal strips to one another. The surface area ofthese test metals are in approximately the same relative proportions toone another as they would be in a representative automotive coolingsystem. The ratio of test metal surface area to coolant is alsoapproximately the same as in the automotive cooling system.

The glass rod is adjusted so that the test bundle is immersed in thetest solution. The glass cell is then placed in an oil bath maintainedat a temperature of F. and air is bubbled into the test solution throughthe air inner tube at a rate of 50 milliliters per minute. The air waspreviously scrubbed free of any carbon dioxide by passing it through a20 wt. percent aqueous solution of caustic. The cell is maintained in anoil bath for a period of 161 hours whereupon the test bundle is removed.Each test metal strip is freed of corrosion prod ucts by scrubbing witha household basic cleaner and a soft cloth and successively rinsed indistilled water and acetone. Each test metal strip is then dried andreweighed with the weight loss being calculated on the basis ofmilligrams lost per square decimeter of original surface area of thetest metal strip (mg/sq. dm.).

Seven antifreeze compositions were subjected to the above test and weredesignated as Antifreeze A through G, in-clusively. Antifreeze A is anuninhibited ethylene glycol. Antifreeze B is an example of theantifreeze of the parent application. Antifreezes, C, D, E, and F arethe same as Antifreeze B except they contain examples of one of thecomponents of our storage stability combination. Antifreeze G representsthe storage stabilized antifreeze combination of the invention.

The test data and results are reported below in Table I:

tion of the invention is subjected to the above described storage test.In addition, undiluted Antifreeze B containing one of the components ofthe storage stabilizing TABLE I A B C D E F G Comp. Antifreeze, Wt.Percent:

Ethylene Glycol 100 95. 50 95.40 95.00 94. 50 95.00 95.30 0.80 0. 800.80 0. 80 0. 80 O. 80 1. 25 1. 25 1. 25 1. 25 1. 25 1. 25 0.11 0. 11 0.11 0. 11 0. 11 0. l1 0. 25 0. 25 0. 25 0. 25 0. 25 0. 25 0.10 0.10 0.100.10 0.10 0.10 0.50 0.50 0.50 0.50 0. 50 0.50 0.10 0.50 1.00 0.10 0.400. 10 Water 1. 49 1 49 1. 49 1 9 1.49 1. 49 Composition of Diluted Antieeze,

Wt. Percent:

Water (200 p.p.n1. Cl 75 75 75 75 75 75 75 Antifreeze" 25 25 25 25 25 2525 Corrosion Loss, mgJsq. dm.:

Brass 3 1 +1 +2 +3 +2 7 +2 +1 0 0 +2 0 56 20 20 1 71 31 2, 095 4 3 0 014 0 2, 210 +3 +2 4 169 +14 Cast Aluminum 20 239 150 88 110 652 164 Ascan be seen from the above, Antifreeze G, the representative of theantifreeze of our invention, gives essentially the same corrosionprotection to brass, copper,

combination and undiluted Antifreeze B per se are testedfor comparison.The test data and results are reported below in Table II:

TABLE II.AI ITIFREEZE B WITH AND WITHOUT STABILITY ADDITIVE StorageStabilizing Additive Cone. Days Before Precipitate Forms Additive,Weight Room 100 F. 120 F. 135 F. Percent Temp.

None Triethanolamine.--

TEA Na Salt of EDTA.--"

solder, steel and cast iron as Antifreeze B, which is identical toAntifreeze G except that it does not contain the novel storageincreasing combination. However, in respect to aluminum, the antifreezecomposition of the in-.

EXAMPLE IV This example illustrates the outstanding storage propertiesof the antifreeze formulation of the invention.

The storage test procedure is as follows:

A 4" strip of black iron out from a black iron drum is placed in avertical position in a glass bottle. To the bottle there is added theantifreeze test solution in an amount to cover all but the top /2" ofthe test strip. The bottle is then stored under quiescent conditions andmaintained at a constant temperature. The period of time in days ittakes for a precipitate to form in the bottom of the bottle at a giventemperature is recorded.

Undiluted Antifreeze B described in Table I containing an example-of thestorage stability additive combina- Referring to the data in above TableII the outstanding storage stability properties of our additivecombination can be seen. For example, at a storage temperature of 135 F.when no additive is present the period of stability is for only threedays. When 0.2 wt. percent triethanolamine is added this is increased tofourteen days, 0.4 wt. percent triethanolamine increases it sixteendays, and 0.6 wt. percent triethanolamine further increases storage totwenty-one days. When the sodium salt of the ethylenediamine tetraaceticacid (Na salt of EDTA) is substituted for triethanolamine in an amountof 0.2 wt. percent, the storage stability is further increased tothirty-eight days, and the amount of 0.4 wt. percent sodium salt of EDTAstill further increases storage stability to forty-three days. However,when the combination of triethanolamine and the sodium salt of EDTA isemployed in an amount of 0.3 wt. percent each for a total additiveamount of 0.6 wt. percent, the storage stability increases to days. Inother words, our additive combination is over 4 times more effectivethan an equivalent amount of triethanolamine and 2 times more effectivewhen almost an equal amount of sodium salt of EDTA is employed.

'In addition to the foregoing, a comparison of the data in Table I andTable II shows that there appears to be no correlation between theeffectiveness of an alkanolamine and the alkylenediamine tetraalkanoicacid material in inhibiting corrosion in automotive cooling systems andthe effectiveness of these same ingredients in prolonging the storagestability of antifreeze. For example, it is seen in Table I that theaddition of triethanolamine substantially reduces corrosion while theaddition of the sodium salt of EDTA substantially increases corrosion ofcast iron and cast aluminum. Such data would indicate that the sodiumsalt of EDTA would be less effective as a storage stability additivethan triethanolamine and in fact would promote storage instability.Contrary to such an assumption, it can be seen from Table II that theethanolamine is less effective alone than said sodium salt alone instorage stability. Further an interaction takes place between theantifreeze ingredients and the container when both are in combinationwith the storage stability additive resulting in a synergistic increasein the storage stability of the antifreeze. The foregoing demonstratesthe unexpected results of our storage stability additive combination inthe contemplated antifreeze formulations.

We claim:

1. A storage stabilized antifreeze composition consisting essentially ofa water soluble freezing point depressant alcohol, between about 1 and 9wt. percent of an inhibitor combination and between about 0.05 and 0.8Wt. percent of a storage stability additive, said combination consistingessentially of between about 24 and 27 wt. percent alkali metaltetraborate, between about 36 and 45 wt. percent alkali metalmetaborate, between about 4 and 5 wt. percent alkaline earthtetraborate, between about 6 and 10 wt. percent alkaline earth metalmetaborate, between about 13 and 22 wt. percent alkali metal arseniteand between 3 and 4 wt. percent alkali metal mercaptobenzothiazole, andsaid additive consisting essentially of an alkanolamine of the formula:

y is a whole integer from 1 to 3, inclusively, and an alkylenediaminetetraalkanoic acid material of the formula:

where R is an alkylene radical from 2 to 3 carbons, R is an alkyleneradical from 1 to 3 carbons, and Z is a member selected from the groupconsisting of hydrogen, alkali metal and mixtures thereof, and saidalkanolamine to said acid material being present in a weight ratio ofbetween about 1:1 and 1:2.

2. A storage stabilized antifreeze composition in accordance with claim1 wherein said combination also includes between about 0.5 and 2.5 vol.percent of an added oil phase inhibitor based on the volume of saiddepressant, said oil phase inhibitor consisting essentially of betweenabout 95 and 99. 5 wt. percent lubricating oil and between about 0.5 and5 wt. percent of a C0 neutralized basic alkaline earth metal hydrocarbonsulfonate and having a molecular weight between about 900 and 1500.

3. A storage stabilized antifreeze composition in accordance with claim1 wherein said depressant is ethylene glycol, said alkali metaltetraborate is borax, said alkaline earth metal tetraborate is calciumtetraborate, said alkali metal metaborate is sodium metaborate, saidalkaline earth metal metaborate is calcium metaborate, said alkali metalarsenite is sodium arsenite, said alkali metal mercaptobenzothiazole issodium mercaptobenzothiazole, said alkanolamine is triethanolamine, andsaid alka'noic acid material is the tetrasodium salt of ethylenediaminetetraacetic acid.

4. A storage stabilized antifreeze composition in accordance with claim2 wherein said depressant is ethylene glycol, said alkali metaltetraborate is borax, said alkaline earth metal tetraborate is calciumtetraborate, said alkali metal metaborate is sodium metaborate, saidalkaline earth metal metaborate is calcium metaborate, said alkali metalarsenite is sodium arsenite, said alkali metal mercaptobenzothiazole issodium mercaptobenzothiazole, said alkanolamine is triethanolamine, saidalkanoic acid material is the tetrasodium salt of ethylenediaminetetraacetic acid, said oil is a naphthenic lubricating oil having aSaybolt Universal viscosity between 50 and 100 at 100 F. and an APIgravity between 20 and 28 and said sulfonate is a C0 neutralized basicbarium dialkylbenzene .sulfonate having a molecular weight between 1100and 1300 and a barium content between 21 and 25 wt. percent based onsaid sulfonate,

5. An aqueous antifreeze composition consisting essentially of betweenabout 40 and vol. percent water, between about 20 and 60 vol. percentwater soluble freezing point depressant, said freezing point depressantcontaining between about 1 and 9 wt. percent of an inhibitor combinationand between about 0.05 and 0.8 wt. percent of a storage stabilityadditive, said inhibitor combination consisting essentially of betweenabout 24 and 27 wt. percent alkali metal tetraborate, between about 36and 45 wt. percent alkali metal metaborate, between about 4 and 5 wt.percent alkaline earth metal tetraborate, between about 6 and 10 wt.percent alkaline earth metal metaborate, between about 13 and 22 wt.percent alkali metal arsenite, between about 3 and 4 wt. percent alkalimetal mercaptobenzothiaziole and said storage stability additive,consisting essentially of an alkanolamine of the formula:

where R is an alkylene radical having from 2 to 3 carbons and y is aninteger from 1 to 3, .inclusively, and an alkylenediamine tetraalkanoicacid material of the formula:

where R is an alkylene radical of from 2 to 3 carbons, R is an alkyleneradical from 1 to 3 carbons, and Z is a member selected from the groupconsisting of hydrogen, alkali metal, and mixtures thereof, the weightratio of said alkanolamine to said material being between about 1: 1 and1:2.

6. An aqueous antifreeze in accordance with claim 5 wherein there isalso included between about 0.5 and 2.5 vol. percent oil phase inhibitorbased on said freezing point depressant, said oil phase consistingessentially of between about and 99.5 wt. percent lubricating oil andbetween about 0.5 and 5 wt. percent of a C0 neutralized basic alkalineearth metal hydrocarbon sulfonate having a molecular weight betweenabout 900 and 1500.

References Cited by the Examiner UNITED STATES PATENTS 2,126,173 8/1938C-lapsadle et al. 25275 2,681,891 6/1954 Bos et a1 25275 2,803,6038/1957 Meighen 25275 2,886,531 5/1959 Fiser 252-75 2,960,473 1 1/ 1960Meighen et a1 252-75 3,079,343 2/ 1963 Bernard 252--75 ALBERT T. MEYERS,Primary Examiner.

JULIUS GREENWALD, Examiner.

I. D. WELSH, Assistant Examiner.

1. A STORAGE STABILIZED ANTIFREEZE COMPOSITION CONSISTING ESSENTIALLY OFA WATER SOLUBLE FREEZING POINT DEPRESSANT ALCOHOL, BETWEEN ABOUT 1 AND 9WT. PERCENT OF AN INHIBITOR COMBINATION AND BETWEEN ABOUT 0.05 AND 0.8WT. PERCENT OF A STORAGE STABILITY ADDITIVE, SAID COMBINATION CONSISTINGESSENTIALLY OF BETWEEN ABOUT 24 AND 27 WT. PERCENT ALKALI METALTETRABORATE, BETWEEN ABOUT 36 AND 45 WT. PERCENT ALKALI METALMETABORATE, BETWEEN ABOUT 4 AND 5 WT. PERCENT ALKALINE EARTHTETRABORATE, BETWEEN ABOUT 6 AND 10 WT. PERCENT ALKALINE EARTH METALMETABORATE, BETWEEN ABOUT 13 AND 22 WT. PERCENT ALKALI METAL ARSENITEAND BETWEEN 3 AND 4 WT. PERCENT ALKALI METAL MERCAPTOBENZOTHIAZOLE, ANDSAID ADDITIVE CONSISTING ESSENTIALLY OF AN ALKANOLAMINE OF THE FORMULA: